Suspension for extendable typewriter shelf



c 1956 H. E. HUTZELMAN 2,766,091

SUSPENSION FOR. EXTENDABLE TYPEWRITER SHELF Filed Feb. 8, 1955 3 Sheets-Sheet 2 K 159 Q E flggfi w INVENTOR.

Hwmd EHuzdmam Q ATTOE MEY 1956 H. E. HUTZELMAN 2,766,091

SUSPENSION FOR EXTENDABLE TYPEWRITER SHELF Filed Feb. 8, 1955 3 Sheets-Sheet 3 INVENTOR.v ware! llama/m2 A TTOQNEY 2,7 66,091 SUSPENSZON FOR EXTENDABLE TYPEWRITER EELF Howard E. Hutzehnan, Corry, Pa., assignor to Corry- Jamestown Manufacturing Corporation, Corry, Pa., a corporation of New York Application February 8, 1955, Serial No. 486,925 Claims. (Cl. 31227) substantially balanced at all times; that is, throughout the position of storage.

Swing mechanisms for typewriter shelves are provided with weights or springs which serve as counterbalances to at least partially relieve the load torque of a combined shelf and typewriter for convenient manipulation into and out of position of use. Even assuming that prior structures of this nature have been designed to subtantially balance the load or weight torque throughout the entire path of travel of a combined shelf and typewriter, as is set pending application, such structure is still not entirely satisfactory for its intended purpose. Generally, swing mechanisms are provided with counterbalance structure that is best suited and most satisfactorily operated with an intermediate size and weight typewriter. It is presumed that this is due to the fact that intermediate weight and size typewriters are in more common use than those of greater or lesser weight and size. Since the counterbalance structure of prior swing mechanisms was designed for an intermediate weight, it appears obvious that such structure would be too strong for use with small, light weight typewriters such, for example, as the portable type. Thus, any such mechanism would be difficult to manipulate or would operate in such manner as to get out of control of the operator. In other words, such a counterbalance structure would over balance the load of typewriter and shelf, causing it to move with undesired rapidity into retracted or extended position, with the possibility of damage thereto. On the other hand, a large or heavy typewriter would be of greater weight than the capacity of the counterbalance structure and necessitate an operators exerting considerable force to raise the shelf and typewriter into position of use. Also, since the counterbalance structure was incapable of balancing the shelf and typewriter during movement to position of use, it would permit out-of-control, pendulum-like movement of the typewriter and shelf into position of rest, if an operator did not exert considerable force by which to supplement the inadequacy of the counterbalance structure.

It is a purpose and object of the present invention to provide a swing mechanism for a pedestal contained typewriter shelf that includes counterbalance structure which is adaptable for controlling the combined load or weight torque of shelves and typewriters of different sizes.

Another object of the invention lies in the provision of structure which will enable adjusting the tension of a counterbalance mechanism to enable ready and convenient control by an operator of shelves and typewriters of different sizes and weights.

A further object of the invention lies in the provision of mechanism which enables the convenient and easy adjustment of the tension of a counterbalance structure without the need of disassembling to any extent the swing mechanism, the counterbalance, or the enclosure for the structure.

A still further object of the invention lies vision of structure which enables not only adjustment of a counterbalance mechanism but the removal and replacement of the tensioning parts thereof without in any way dismantling any of the structure.

Other objects and advantages of the invention will be more fully understood from a consideration of the following specification, taken in conjunction with the accompanying drawings, in which Fig. 1 is a fragmentary interior side view, partly in section, of a typewriter shelf swing mechanism and shows a spring tension control device in position for use;

Fig. 2 is a fragmentary plan view of the structure of Fig. 1;

Fig. 3 shows a portion of the structure shown in Fig. 1 with the tension control device partially operated to enable resetting the tension of the springs of the counterbalance;

Fig. 4 is a view similar to Fig. 1, showng a further operative position of the control device during the operation of changing the tension of the counterbalance springs;

Fig. 5 is a View similar to Fig. 3, showing the arrangement of the control device when it is to be used to relieve spring tension and enable removal and replacement of the springs;

Fig. 6 is a fragmentary plan view, showing the position of the various parts of the structure as they appear in Fig. 3;

Fig. 7 is a fragmentary plan view of the various parts as they appear in Fig. 4;

Fig. 8 is a fragmentary positions of the parts as they appear in Fig. 5;

Fig. 9 is an enlarged fragmentary vertical sectional View taken substantially on the line 99 of Fig. 5; and

Fig. 10 is a fragmentary side elevational view of one supporting side rail for the swing mechanism showing the various positions for securing a spring-engaged cross bar and the positions for the control device.

Referring more particularly to the drawings, the reference numeral 10 is employed to generally designate a pedestal of the type common to desks or tables. The pedestal, in the present disclosure, consists of inner and outer duplicate side walls 11, rear wall 12 and base wall 13. The side walls are flanged along their front edges, as at 14, to form an opening 16 adapted to be closed by a side hung door. The top 17 of the pedestal generally constitutes a part of a desk or table top. The pedestal is reinforced interiorly by front and rear channels 18 which extend transversely of and are permanently secured to the inner face of the base wall 13 of the pedestal. A shallow frontal panel 19, at least in part, frames the opening 16. The side walls 11 are reinforced by front and rear channels 21 that are permanently attached to the inner face of these walls and are in vertical alignment with the base channels 18. The suspension is carried in its entirety by a pair of side rails 22 which are of the nature of channels. The flanged edges 23 are intended to abut the outstanding base walls of the side channels 21 and are secured thereto in any suitable manner, as by screws 24. At the forward ends of the rails 22 there is in the proplan view, showing the various a channel bar 26 that forms a part of the reinforcement of the pedestal. Beneath this bar, the laterally projecting central portion 27 of the rail is formed with a forwardly opening notch 28 (see Fig. 10), the lower wall of which is inclined slightly downwardly. From this wall, the portion 27 is cut away at an incline and the flange 23 therebeneath is also cut away substantially as suggested in the above mentioned figure of the drawings. Adjacent the forward edge of the channels 21, the upper flange 23 of the supporting rails 22 is provided with a series of slots 29, preferably three in number. djacent the rear edge of the side channels 21 are three further slots 31 in the flange 23, slots 31 being spaced considerably farther apart than slots 2?. A cross bar 32 extends from one side to the other of the pedestal, the ends of the bar resting on top of the outwardly projecting side of the side rails 22. This bar is intended to secure the forward ends of counterbalance springs 33. To secure the bar against tension of the springs, two tapered arms 34 are provided. The narrower end of each arm is secured to the top surface of the bar 32 by a pivot 35. Adjacent the pivot end, the arm is offset downwardly, as at 36, in order that the remainder thereof may be in the plane of the under surface of the bar. At its other end, arm 34 is formed with a book 37 which, as will hereinafter be brought out, is engageable with any of the slots 29 and 31 formed in the flange 23 of the side rail 22.

A typewriter shelf 33 consists of a flat top portion that is rigidified by suitable marginal flanges. The rear portions of the side flanges mount brackets 39 which do not extend above the shelfs surface but depend below it and include rear portions 41 and central portions 42. The suspension for the shelf 38 is carried by the rails 22 and includes a forward pair of arms 43 which, at their upper ends, are attached for pivotal movement to these rails approximately midway of their length. The lower ends of these arms are pivotally joined to the forward ends of the shelf brackets 39. A rearward pair of suspension arms 44 is provided. The upper ends of these arms are pivotally secured to the extreme rear lower ends of the rails 22. The lower ends of these arms are joined to the lower ends of the rear portions 41 of the brackets 39. The structure thus far described provides a suspension for the shelf that enables swinging movement thereof through an are from position of storage to position of use.

Attention is now directed to the structure having to do with the control and manipulation of the counterbalance springs 33. This structure includes a member 46 that consists of a cross bar 47 and integral end legs 48. The bar portion of the member is engaged by the other ends of the counterbalance springs 33. The ends of the legs 48 are pivotally joined to the rear suspension arms 44 a short distance from the pivots of these arms with the rails 22. Control links 49 are provided, the lower end of each being pivotally joined to the leg 48 approximately onethird of the length of the leg from the cross bar 47. Centrally, each link is laterally offset for clearance purposes in its manipulation. The other end of each link is pivotally connected to the rail 22 at a point above and forwardly of the upper pivotal connections of each arm 44 with the rail. It is to be noted that the legs 48 of the member 46, together with links 49 and the upper ends of suspension arms 44, comprise triangular units which, by reason of two different but proximate pivots, provide such a path of movement of the cross bar 47 as to produce a specific and prescribed path of travel for said bar. Assuming the forward ends of the springs 33 to be stationary by reason of their attachment to cross bar 32, it will be noted that the rear ends of the springs, being attached to cross bar 47, will follow the travel of this cross bar and extend or contract in accordance therewith. As fully brought out in my above mentioned pending application, this particular structure functions to provide a torque in the springs such that they will hold the shelf in fully retracted position and also serve as a varying force to substantially equal the weight torque of the shelf and typewriter mounted thereon and to a progressive ex tent as the weight torque of these parts increases as a result of movement of the shelf from a depending, suspended position into a raised position of use.

As has already been set out, the present invention is intended to enable changing the torque of the counterbalance springs to accommodate the swing structure to the accurate counterbalancing of typewriters of different weights. To this end, the forward end of the counterbalance springs 33 have been attached to the cross bar 32 and the cross bar in turn provided with arms 34 that can be moved from one position to another along the side rails 22 for the purpose of increasing or decreasing the initial tension of the springs 33. It is a general practice, in the assembly of the swing suspensions herein described, to set the springs at an intermediate tension inasmuch as such tension will best counterbalance the weight torque of a large class of conventional typewriters. It frequently occurs, however, that a desk or table in which this structure is mounted is presented to a purchaser who requires a larger and heavier typewriter. In such an instance, the originally set tension of the springs 33 is insufficient to properly counterbalance the weight torque of a heavy typewriter. It will, of course, be appreciated that regardless of the initial tension of the springsthat is, whether they be set for a light or medium weight typewriter-they are normally under considerable tension and it woud be impossible to manually extend them to an extent to adjust the bar 32 and enable withdrawing the hooks 37 from a given pair of slots and re-engage them with other slots.

To enable initial assembly of these springs, changing their tension, or replacing them in the field, it is proposed to provide a simple tool that is easily operable and without special skill and without in any way dismantling any part of the suspension. This tool, generally indicated by the reference numeral 51, consists of two parts; namely, a Y-shaped operative part 52 and a handle 53. The base of the part 52 is joined, through a pivot 54, to one end of the handle 53. The Y arms 56 of the part 52 terminate in oppositely extending books 57. Adjacent the pivot 54, one face of the handle mounts a headed pin 58. As will be more clearly understood from a description of the operation of this tool, it is provided with duplicate arms and hooks in order that it may be operable at either side of the pedestal and be supported while in use by either of the side rails 22 that carry the suspension.

Although it has been stated that the assembly of the presently disclosed suspension is generally, initially set for intermediate tension of the springs 33 to counterbalance the weight torque of an intermediate weight typewriter, the drawings show the springs to be set for a lesser tension-namely, to counterbalance the weight of a light weight typewriter. In other words, the. hooks 37 of arms 34 are engaged with the rearmost slots 29 of the rails 22. The following description of resetting the tension of the springs presupposes that it is desired to increase the tension of the springs so that they will effectively counterbalance the weight torque of a heavy typewriter. The tool 51 is projected through the opening 16 into the pedestal and the uppermost hook 57 is engaged with the cross bar 32 adjacent one end thereof, substantially as suggested in Figs. 1 and 2. At the same time, -tl1e pin 58 is projected into the open notch 28. The handle 53 is now swung downwardly, pivoting about the pin 58, and causing the short end thereof to move forwardly and draw the part 52 toward the front of the pedestal. Initial movement of the handle relieves the pull on the book 37 and allows the operator to swing the arm and withdraw the book from the rearmost slot 29. Continued downward movement of the handle 53 moves the hook 37 forwardly past the middle slot and brings it into alignment with the foremost slot. At this amber point, the arm is swung to project the hook 37 into the foremost slot. The handle is now withdrawn to its original straight line position, and the tool is removed after disengaging the hook 58 thereof from the bar 32 and the pin 58 from the slot 28. The tool 51 is now turned over and the other hook 57 thereof engaged with the other end of the bar 32. Similarly, the pin 58 is projected into the slot 28 of the other rail 22. Operation of the tool on this side is identical with that above described and enables bringing forward the other end of the bar 32. Whatever .the distance may be between the rearmost and forwardmost slots 29, it is evident that the springs 33 have been stretched or elongated that distance and, therefore, they will be under greater initial tension than prior to the resetting above described. Conversely, it is quite simple to decrease the spring tension by means of the tool 51 by changing engagement of hooks 37 from the foremost slots 29 to the intermediate or rearmost slots.

It is possible, through the use of the tool 51, in conjunction with the described suspension, to relieve all tension on the springs and enable removal and replacement thereof. As has already been mentioned, springs 33 are not susceptible to manual manipulation and, therefore, it would be impossible, when it is desired to remove a spring, :to merely unhook it from the bar 32. The tool 51, for this purpose, may have its pin 58 engaged with the foremost of the several keyhole slots 59 provided in the central portion of the rail 22. The uppermost hook 57 of the tool is engaged with the bar 32 by moving the handle 53 downwardly and inwardly of the pedestal to approximately the dotted line position shown in Fig. 5. In this position, the tool has slightly stretched the springs to enable disconnecting the hook 37 from the channel slot 29. The handle 53 is then swung outwardly, allowing one end of the bar 32 to move rearwardly, thus partially decreasing the tension of the adjacent spring. As the handle continues its outward movement, hook 37 becomes aligned with the foremost slot 31 and may be engaged therewith. The tool is then mounted and operated in the same manner on the other side of the pedestal. It will be found that there is still considerable tension in the springs 33 and the tool is therefore again utilized by locating the pin 58 in the middle keyhole slot 59. The hook 57 thereof is engaged with the bar 32 and operated to release the hook arm 37 and allow further contraction of the spring to the extent that the hook 37 may engage the middle slot 31. By the time the tool has been operated from the intermediate keyhole slot 59 to disengage the arm hook 37 from the innermost slot 31, all tension of the spring 33 will have been relieved. At this point, the spring may be manually disengaged from bars 32 and 47 and, of course, replaced with weaker or stronger springs.

Although applicant has shown and described a specific swing mechanism for a pedestal contained typewriter shelf in conjunction with structure enabling adapting the counterbalance of such mechanism to use with typewriters of different weights, it will be understood that variations in this structure may be made and are contemplated insofar as they are within the spirit and scope of the invention as set out in the annexed claims.

Having thus set forth my invention, what I claim as new and for which I desire protection by Letters Patent is:

l. The combination of a spring loaded suspension for a pedestal contained typewriter shelf having pedestal supported side rails mounting the upper ends of swingable parallel arms that serve to suspend said shelf, swingable linkage joined to certain of said arms and said rails, a cross bar supported at its ends for selective positional connection with said rails and tension springs connecting said linkage with said bar; with a device for changing the tension of said springs, said device comprising a pair of pivotally connected members, one of said members having pivotal engagement with one of said rails, means on the other of said members capable of hook-like engagement with said bar, said one member being manually swingable about its pivotal engagement with one of said rails to effect movement of the other of said members in a direction to control the tension of said springs on said bar and enable moving said bar to another selective position of connection with said rails whereby to alter the spring loading of said suspension.

2. The combination of a spring loaded suspension for a pedestal contained typewriter shelf having pedestal supported side rails, said rails having suitably arranged slots, said rails mounting the upper ends of swingable parallel arms that serve to suspend said shelf, swingable linkage joined to certain of said arms and said rails, a cross bar mounted at its ends on said rails, arms pivotally joined to the ends of said bar, the free ends of said arms having selective engagement with one of said slots in each of said rails, and springs under tension connecting said linkage with said bar; with a device for changing the tension of said springs, said device comprising a pair of pivotally connected members, one of said members having pivotal engagement with one of said rails, means on the other of said members capable of hook-like engagement with said bar, said one member being manually swingable about its pivotal engagement with one of said rails to effect movement of the other of said members in a direction to increase the tension on said springs, enable withdrawal of said arms from engagement with said rails and the reengagement of said arms with other slots in said rails.

3. The combination of a spring loaded suspension for a pedestal contained typewriter shelf having pedestal supported side rails mounting the upper ends of swingable parallel arms that serve to suspend said shelf, swingable linkage joined to certain of said arms and said rails, a cross bar supported at its ends for selective positional connection with said rails, and tension springs connecting said linkage with said bar; with a device for changing the tension of said springs, said device comprising a pair of pivotally connected members, a pin on one of said members engageable with an end slot in either of said rails, said pin enabling pivotal movement of the one member with respect to said rails, a hook on the free end of the other of said members engageable with said bar, the one member, when manually rotated about said pin, effecting movement of the other of said members in a direction to extend said springs sufiiciently to enable moving said bar to another selective position of connection with said rails whereby to alter the spring loading of said suspension.

4. The combination of a spring loaded suspension for a pedestal contained typewriter shelf having pedestal supported side rails mounting the upper ends of swingable parallel arms that serve to suspend said shelf, swingable linkage joined to certain of said arms and said rails, a cross bar supported at its ends for selective positional connection with said rails, and tension springs connecting said linkage with said bar; with a device for changing the tension of said springs, said device comprising a pair of pivotally connected members, a pin on one of said members engageable with an open ended slot at the forward end of each of said rails, said pin providing for pivotal movement of the one member with respect to said rails, opposed hooks on the free end of the other of said mem bers, one of said hooks being engageable with said bar when said device is engaged with one rail and the other of said hooks being engageable with said bar when the device is inverted and engaged with the other of said rails, the one member, when manually rotated about said pin, effecting movement of the other of said members in a direction to extend said springs sufficiently to enable moving said bar to another selective position of connection with said rails whereby to alter the spring loading of said suspension.

5. The combination of a spring loaded suspension for a pedestal contained typewriter shelf having pedestal supported side rails mounting the upper ends of swingable parallel arms that serve to suspend said shelf, swingable linkage joined to certain of said arms and said rails, a cross bar moiinted at its ends on said rails, arms pivotally joined to the ends of said bar, the free ends of said arms having selective engagement with a series of slotsin each of said rails, and springs under tension connecting said linkage with said bar; with a device for changing the tension of said springs, said device comprising a manually operable handle and an operative member, these parts being pivotally joined at their adjacent ends, a pin on said handle adjacent its pivotal connection with said member, said pin being engageable with an open ended slot at the forward end of each of said rails, said pin providing for pivotal movement of said handle with respect to said rails, opposed hooks on the free end of said member, one of said hooks being engageable with said bar when said device is engaged with one rail and the other of said hooks being engageable with said bar when the device is inverted and engaged with the other of said rails, said handle, when rotated about said pin, effecting movement of said member in the direction of the length of said rails to extend said springs sufficiently to enable withdrawal of said arms from engagement with said rails and the re-engagement of said arms with other slots in said rails.

References Cited in the file of this patent UNITED STATES PATENTS 

